In general, in the case of performing a grading work using an excavator, it is required for a skilled operator having a long operating experience to perform an appropriate operation to linearly control the trace of a bucket end due to a complicated link structure of an attachment, such as a boom or an arm. In order to smoothly perform such an operation, automation technology to control the track using an angle sensor for measuring the pose of the attachment or a cylinder displacement sensor has been attempted.
Such automated grading work requires high costs, and during the automated grading operation, the operation of the attachment is limited to a set speed regardless of an operator's operation amount of the attachment. Further, if an operator simultaneously performs another type of work, it is necessary to repeatedly change the automated function setting and automated function release every time, and thus the operator's work fatigue is increased and the work efficiency is lowered.